Мы не будем играть в футбол в воскресенье.

Solution:

Translate the Russian sentence 'Мы не будем играть в футбол в воскресенье.' into English using the Future Simple tense.

1. Identify the subject: 'Мы' (We).
2. Identify the negation and verb: 'не будем играть' (will not play).
3. Identify the sport: 'в футбол' (football).
4. Identify the day: 'в воскресенье' (on Sunday).
5. Combine these elements into a Future Simple sentence.

Answer: We will not play football on Sunday.